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| Use an ND grad to retain detail in the sky when shooting landscapes |
What’s your favourite filter for black & white photography? If someone had asked me that question a few years ago, I would have answered ‘red’. Today the answer is ‘ND grad’, because just as digital capture has changed our approach to black & white photography, it has also changed the filters we need to use.
Coloured filters were the mainstay of monochrome photographers for decades. They used to change the way certain colours produced tones and were used to boost contrast. However, these filters are no longer required because you can replicate their effects digitally. This is just as well – there’s little point putting a deep-red filter on your camera lens when you’re shooting in colour, even if the final image will be black & white. Filters aren’t totally redundant, though, and there are four I use almost daily.
POLARISERS
The main purpose of polarising filters may be to boost colour saturation, but they also do other things. For example, they eliminate reflections in water, glass and other reflective surfaces, reduce glare, improve clarity and enhance the sky, all of which can benefit a black & white image whether shot on a dull day or in full sun.
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| Coloured fi lter effects can be applied digitally to black & white images |
If you shoot a waterfall or a river, a polariser can be used to remove glare from the wet rocks and foliage, and reflections in the water, while its 2-stop light reduction will also allow you to use a slower shutter speed to blur the water. In sunny weather, a polariser will darken a blue sky just as well as a red filter would when used with black & white film – but without changing the tonality of the other colours in the image. Also, if you use a polariser to boost saturation in a colour image and then convert that image to black & white, you’ll benefit from stronger tones.
In other words, a polariser is just as useful for digital black & white photography as it is for colour, so don’t leave home without one.
ND GRADS
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| Weaker ND filters are handy for blurring water |
The dynamic range of a digital camera sensor is limited compared to the dynamic range of black & white negative film. Neutral Density (ND) grads help you deal with this by toning down the brightness of the sky or other large areas in a scene so that contrast is reduced enough to bring it within the dynamic range of your camera.
I rarely used ND grads when shooting black & white film because the dynamic range of the film was wide enough to record detail in the highlights and shadows, and the sky could be burned in during printing. But with a digital camera it’s different. Omit the ND grad and there’s a strong chance that the sky will ‘blow out’ – whichmeans it overexposes to the point where no details records. By sliding an ND grad over the lens to cover the sky, you can prevent this and record the sky in all its glory.
I carry a set of three Lee Filters ND grads in 0.3, 0.6 and 0.9 densities. They tone down the sky by 1, 2 and 3 stops respectively. I rarely use the 0.3ND grad but it’s useful when shooting scenes and their refl ection in still water. A 0.6ND grad is best for general use, while the 0.9 is necessary in more contrasty conditions, such as at dawn and dusk.
I favour ‘hard-edged’ grads over ‘soft-edged’ as the density is more consistent and I align them while looking through the camera’s viewfinder. If you struggle with this method, try live view. I also position the ND grad on the lens before taking an exposure reading. In the days of centre-weighted metering this often resulted in overexposure, but today’s multi-pattern ‘intelligent’ metering systems take ND grads in their stride.
10-STOP NEUTRAL DENSITY FILTERS
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| A 10-stop ND filter allows you to record motion in a scene |
The most fashionable filter among black & white photographers at the moment is the 10-stop ND filter, which reduces the light entering your lens by 1,000x, forcing you to use exposures of several minutes in broad daylight. The effects are fantastic, as moving water turns to milk, clouds record as graceful streaks, and people and traffic disappear from busy streets. If you’ve ever wanted to create fine-art monochrome masterpieces from ordinary scenes, this is the filter to use. Be warned, though, because once you try one, you’ll be hooked.
These filters are available from B+W (www.bpluswfilters.co.uk), Hitech (www.teamworkphoto.com) and Lee Filters (www.leefilters.com). There is a long waiting list for the Lee Big Stopper, but Hitech makes an equivalent specifically for the Lee filter holder. Just ask for one with a 1.5mm gasket, rather than the 3mm gasket needed for the Hitech 100 holder.
Your camera’s autofocusing and metering won’t work with a 10-stop ND on your lens, and you won’t be able to see through the viewfinder because it’s so dense. Live view is sensitive enough to see through a 10-stop ND filter on some DSLRs, but your best bet is to compose the scene, align your ND grad if you’re using one, set the shutter to Bulb (B), focus the lens manually, take a meter reading
without the 10-stop ND in place, calculate the exposure, pop the ND on the lens and open the shutter with a remote release. You can calculate exposure for a 10-stop ND filter by multiplying the shutter speed by 1,000. For example, if the correct exposure without the ND in place is 1/15sec, once it is in place it will be 1/15x1,000 = 66secs.
NEUTRAL DENSITY FILTERS
If you don’t fancy the idea of using a 10-stop ND filter, weaker neutral density filters can be used to increase exposure times but in much smaller doses. It’s worth carrying both 0.6ND and 0.9ND filters. These increase the exposure by 2 and 3 stops respectively, or 5 stops if used together. ND filters are ideal when shooting waterfalls, rivers, streams and seascapes, as the increased exposure allows you to use a slower shutter speed to blur the moving water. They are also handy when shooting landscapes in windy weather as you can record movement in blowing grass or swaying trees, or to capture movement when shooting crowds of people, such as commuters spilling off a train. A polariser can be used as a 0.6 ND filter because it cuts the light by 2 stops.
USE ONLY WHEN NEEDED
Anything you place in front of your lens is going to have a detrimental effect on its optical quality, and that includes filters. Therefore, only use them when you need to, don’t use more than one unless absolutely necessary and always remove filters that aren’t serving a purpose, such as your polariser, which a lot of photographers leave permanently attached to their lens. Also, keep your lenses clean and scratch-free.
DIGITAL FILTER EFFECTS
There are two easy ways to mimic the effects of colour-contrast controlling filters in Photoshop. If you have a recent version of Photoshop with the Black & White option in the Adjustments dropdown
menu, you can use the presets for Red, Yellow, Green and Blue filters. All you do is open your colour image, go to Image>Adjustments>Black & White to convert the image to mono, and then choose one of the presets and save your changes.
A more traditional option is to use Channel Mixer in Photoshop. Open your image and then go to Image>Adjustments>Channel Mixer and click on the Monochrome tab. To mimic the effects of a coloured filter, set the slider for that colour to 100% and the other two to 0%, so for a red filter set the Red channel slider to 100% and the Green and Blue channel sliders to 0%.
I have used both methods, but these days I prefer to add filter effects using Nik Software Silver Efex Pro (www.niksoftware.com). This is a fantastic software package for black & white conversion that gives you all the controls that you could ever need to create stunning black & white images from colour digital files. In order to add a filter effect, simply open your chosen colour image in Silver Efex Pro and then click on the required colour in the Coloured Filters menu to the right of the preview image. The changes will be saved as a layer, which massively increases the size of the image file, but when you have finished you can go to Layers> Flatten Image to reduce the file size. Remember, though, that the conversion and filter effect will then be permanent additions to the image, so do ensure that you make a copy of your colour image before converting it.
You can see the type of effects you’ll get from the set of images at the top of these pages. The basic rule to remember is that a colour filter lightens its own colour and darkens its complementary colour, so in the red filter image the poppies appear light and the blue sky dark, but in the blue filter image the poppies are almost black and the sky is very light. These characteristics can be used to alter the tonal relationship in a black & white image so that the role of specific elements is played down or increased.
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